Allow the model/api to be changed for the task generation/checking

[jcredland]

Some models handle the task generation and checking much more effectively than others. It would be useful to be able to switch API connections (or models with open router) to pick one specifically for the objectives API prompts.

[Cohee1207]

This is not as simple as it sounds. See:

• SillyTavern/SillyTavern#962
• SillyTavern/SillyTavern#2538
• SillyTavern/SillyTavern#2658
• SillyTavern/SillyTavern#2822

[jcredland]

Oh well that's a bigger rabbit hole than I was imagining ...

I was kind of hoping I could patch it with one line to change the OpenRouter model even if it wasn't a fix that'd work for everyone ;-)